Trying to pass a function parameter in Kotlin

Question

I have a function:

fun test(){
    Timber.d("Button Clicked")
}

And I'm trying to pass this function to a fragment. Here is that field inside my fragment.

class MyFragment(val layout: Int) : Fragment() {
     var clickEvent1: (() -> Unit)? = null
}

And this is how I'm setting this field before beginning fragment transaction.

fragment.clickEvent1 = {test()}

My goal is to run this function on my button click inside my fragment.

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     dialog_option_1.setOnClickListener { clickEvent1 }
}

There's an issue with the way I'm doing this because the "test" function does not run. Can someone point me in the right direction? Thanks

Does this answer your question? [Kotiln: pass data from adapter to activity](https://stackoverflow.com/questions/56826346/kotiln-pass-data-from-adapter-to-activity) — milad salimi, Jan 15 '20 at 07:48

score 0 · Answer 1 · answered Jan 14 '20 at 17:57

0

Use

dialog_option_1.setOnClickListener(clickEvent1)

You need to pass the lambda itself to method, so you should use () parentheses instead of {}, which create a new lambda that just does almost nothing in your case.

answered Jan 14 '20 at 17:57

ardenit

3,610
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Sadly doesn't work. setOnClickListener() requires View.OnClickListener. clickEvent1 is a (() -> Unit). :( – SomeKoder Jan 14 '20 at 18:04
Then define clickEvent1 as (View) -> Unit (onClick method receives View parameter) – ardenit Jan 14 '20 at 18:06
Or you can use SAM constructor: `val clickEvent = View.OnClickListener { view -> test() }` – ardenit Jan 14 '20 at 18:08
Alright I got it working with `dialog_option_1.setOnClickListener {clickEvent1?.let { it() }}`, your sulotion seems to work nicely. Thanks a lot! – SomeKoder Jan 14 '20 at 19:00
You can replace `clickEvent1?.let { it() }` with `clickEvent1?.invoke()`. – Tenfour04 Jan 14 '20 at 19:29

score 0 · Answer 2 · answered Jan 15 '20 at 01:05

0

Should be

dialog_option_1.setOnClickListener { clickEvent1() }

if you want to do it like that.

answered Jan 15 '20 at 01:05

Strelok

50,229
9
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Trying to pass a function parameter in Kotlin

2 Answers2